288 research outputs found

    OPTIMAL SLIDING MODE CONTROLLER DESIGN BASED ON WHALE OPTIMIZATION ALGORITHM FOR LOWER LIMB REHABILITATION ROBOT

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    The Sliding Mode Controllers (SMCs) are considered among the most common stabilizer and controllers used with robotic systems due to their robust nonlinear scheme designed to control nonlinear systems. SMCs are insensitive to external disturbance and system parameters variations. Although the SMC is an adaptive and model-based controller, some of its values need to be determined precisely. In this paper, an Optimal Sliding Mode Controller (OSMC) is suggested based on Whale Optimization Algorithm (WOA) to control a two-link lower limb rehabilitation robot. This controller has two parts, the equivalent part, and the supervisory controller part. The stability assurance of the controlled rehabilitation robot is analyzed based on Lyapunov stability. The WO algorithm is used to determine optimal parameters for the suggested SMC. Simulation results of two tested trajectories (linear step signal and nonlinear sine signal) demonstrate the effectiveness of the suggested OSMC with fast response, very small overshoot, and minimum steady-state error

    Study of the Active Compound in the Essential Oil of Myrtus communis L.

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    This study appears of the major volatile compounds in the essential oil of myrtle leaves because of its significant medical and economic benefits. The essential oil composition of Myrtus communis leaves during its flowering stage was determined. six volatile compounds were identified in leaves essential oils, α-Pinene 308 µg/ml, linalool (23.83 µg/ml), Eucalyptol or 1,8-cineole (41.46 µg/ml), Limonene (45.22 µg/ml), α-terpineol (41.73 µg/ml), Geranyl acetate (18.28 µg/ml) were the main monoterpene compounds. α-Pinene was Represents the bulk of the other compounds in the myrtle leave Keywords: Myrtus communis L., myrtle, flowering stage, essential oil, chemical compounds

    A Robust univariate procedure for testing symmetry and normality

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    A New Technique for Simulation the Zakharov–Kuznetsov Equation

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    In this article, a new technique is proposed to simulated two-dimensional Zakharov–Kuznetsov equation with the initial condition. The idea of this technique is based on Taylors' series in its derivation. Two test problems are presented to illustrate the performance of the new scheme. Analytical approximate solutions that we obtain are compared with variational iteration method (VIM) and homotopy analysis method (HAM). The results show that the new scheme is efficient and better than the other methods in accuracy and convergence

    Antenatal Depression and Its Associated Factors: Findings from Kuwait Birth Cohort Study

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    Background: Pregnant and postpartum women are at high risk of depression due to hormonal and biological changes. Antenatal depression is understudied compared to postpartum depression and its predictors remain highly controversial. Aim: To estimate the prevalence of depressive symptoms during pregnancy and investigate factors associated with this condition including vitamin D, folate and Vitamin B12 among participants in the Kuwait Birth Study. Methods: Data collection occurred as part of the Kuwait Birth Cohort Study in which pregnant women were recruited in the second and third trimester during antenatal care visits. Data on antenatal depression were collected using the Edinburgh Postnatal Depression Scale (EPDS), considering a score of ≥ 13 as an indicator of depression. Logistic regression was used to investigate factors associated with depressive symptoms in pregnant women. Results: Of 1108 participants in the Kuwait Birth Cohort study, 1070(96.6%) completed the EPDS. The prevalence of depressive symptoms was 21.03%(95%CI:18.62–23.59%) and 17.85%(95%CI:15.60-20.28%) as indicated by an EPDS ≥ 13 and EPDS ≥ 14 respectively. In the multivariable analysis, passive smoking at home, experiencing stressful life events during pregnancy, and a lower level of vitamin B12 were identified as predisposing factors. Conversely, having desire for the pregnancy and consumption of fruits and vegetables were inversely associated with depressive symptoms. Conclusion: Approximately, one fifth of pregnant women had depressive symptoms indicating the need to implement screening program for depression in pregnant women, a measure not systematically implemented in Kuwait. Specifically, screening efforts should focus on pregnant women with unintended pregnancies, exposure to passive smoking at home, and recent stressful live events
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